DESCRIPTION: (Applicant's Abstract) The proposed study is a further extension of the current project designed to study family and peer influences in the acquisition and maintenance of drug use and abuse within a 5-year age-cohort-sequential design. The focal subjects, initially age 11-15, will have been involved in 11 annual assessments by the end of the currently funded study. In this application, we propose to follow up our sample for four more years until ages 27-31. This would provide complete data on a crucial transition period from adolescence through young adulthood that has had limited examination. The broad array of variables included in our previous data collection efforts on these adolescents, their parents, siblings, and peers, provide a unique opportunity to identify predictors of use and abuse in the post secondary school period. Overall we will be able to examine the period from ages 11 to 31 and combine data on initiation, cessation, maintenance, and consequences of substance use and abuse. In the current project we administer annual questionnaires and a brief standardized clinical interview to identify substance use or dependence. Parents and friends complete similar questionnaires. In addition subjects participate in videotaped problem-solving interactions with a same-sex and opposite-sex spouse /partner or friend. Questionnaires include an assessment of substance use, risk factors and consequences of substance use and abuse as well as information regarding role transitions and satisfaction with roles, and methods used for resolving conflict. Friend questionnaires assess their own substance use and behavior and attitude toward use, the target's use and their relationship with the target. Parents provide data on their own use, perception of the child's use and behavior and attitude toward it, degree of contact, and variables assessing their relationship. With the permission of the subject, transcripts, if relevant, and information regarding employment status, marriage, births, an arrest records are obtained from official sources (e.g., court records, social security administration) and from the employer regarding job performance. The proposed project will continue these assessments bi-annually, with a brief mail questionnaire to all participants in the alternative years. The analytic procedures are state-of-the-art statistical techniques precisely designed for the complexities of longitudinal designs, such as structure equation modeling, latent growth curve analyses, hierarchical linear modeling, general estimating equations, and missing data procedures.